Re: Bash

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著者: Olivier Allard-Jacquin
日付:  
To: guilde
題目: Re: Bash
    Bonjour

Frédéric Mantegazza a écrit :
> Bonjour,
>
> Est-ce que quelqu'un peut m'expliquer les syntaxes suivantes, en shell :
>
>     ${1%.*}


olivier@phoenix:~$ TOTO="aaaaaa.bbb" ;echo ${TOTO%.*}
aaa

    Cela permet de supprimer l'extension d'un fichier


> et
>
>     ${@##*/}


olivier@phoenix:~$ TOTO="aaa/bbbb/cccc" ;echo ${TOTO##*/}
cccc

    C'est utiliser pour récupérer le nom d'un fichier, à partir de son 
chemin complet


> Je connais $1 et $@, mais que font les {}, % et autres ## ?


    man bash :
<extrait>
       ${parameter#word}
        ${parameter##word}
               The word is expanded to produce a pattern just as in 
pathname expansion.  If the pattern matches the beginning of the value 
of parameter, then the result of the expansion is the expanded  value 
of  parameter  with the shortest matching pattern (the “#” case) or the 
longest matching pattern (the “##” case) deleted.  If parameter is @ or 
*,  the  pattern removal  operation is applied to each positional 
parameter in turn, and the expansion is the resultant list.  If 
parameter is an array variable subscripted with @ or *, the pattern 
removal operation is applied to each member of the array in turn, and 
the expansion is the resultant list.
        ${parameter%word}
        ${parameter%%word}
               The word is expanded to produce a pattern just as in 
pathname expansion.  If the pattern matches  a  trailing  portion of the 
expanded value of parameter, then the result of the expansion is the 
expanded value of parameter with the shortest matching pattern (the “%” 
case)  or the longest matching pattern (the “%%” case) deleted.  If 
parameter is @ or *, the pattern removal operation is applied to each 
positional parameter in turn,  and  the expansion  is  the resultant 
list.  If parameter is an array variable subscripted with @ or *, the 
pattern removal operation is applied to each member of the array in 
turn,  and the expansion is the resultant list.


</extrait>

    Cette page de "man" est particulièrement obscure !!!! ;)


> Merci d'avance.


    De rien.


    Cordialement


                        Olivier
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